Timepiece dial



March 18, 1969 w KHLI ET AL 3,433,013

TIMEPIECE DIAL Filed March 15, 1967 Sheet of2 FIGJ FIG.3

United States Patent Oce 3,433,0l3 Patented Mar. 18, 1969 4 s U.s. c. s 127 6 Claims Int. c. G04b 19/06 ABSTRACT OF THE DISCLOSURE A watch dial having time signs afiixed thereto, the signs having at least one projecting foot the length of which slightly exceeds the thickness of the dial plate. The foot, composed of a plastic material, passes through an opening in the dial plate and upon heating Will be fused to the rugosities in the opening.

Already known are timepiece dials of this type in which the time indicia are obtained by injecting liquid plastic material directly on the plate of the dial which is placed in a mould. The tooling necessary for carrying out such a process is costly and a new mould must be especially made for each type of dial. Moreover, the carrying out of such a process is delicate, especially when it is desired to make curved dials. Actually in order to obtain good results, it is necessary that the upper surface of the dial adhere perfectly to the mould. It is known however that the tolerances of curvature of dials are rather wide.

It has also been proposed to glue signs in relief on a dial. If the sign is glued on the surface of the dials, the glue may overrun the periphery of the indicia. To avoid this, the time sign has been provided with a foot which has been introduced in an opening of the dial which opens towards the back side thereof thus providing a lodging around the extremity of the foot, around which is run a varnish. This process when used with a metallic foot necessitates the elimination of the part of the varnish overflowing the lodging and owing to this requires additional manpulations.

Other processes recommend the securing of time signs by coalescing, by ultra-sonic welding. These have 'been utilized with success only in the case of plastic time signs in relief on a plate of plastic material.

The accompanying drawings represent by way of example various modification& of the present process.

FIGURE 1 is a cross-sectional view of a dial with a time sign postioned thereon but not secured thereto.

FIGURE 2 is across-sectional view of the dial with the time sign secured.

FIGURE 3 is a cross-sectional view of a second modification of the invention taken along lines III-III of FIGURES 4 and 5.

FIGURES 4 and 5 are side views of the back of the dial in a second embodiment of the invention.

FIGURE 6 is a cross-sectional view of another modification.

FIGURE 7 is a schematic view of apparatus intended for use in the attaching of time indicia according to the invention.

FIGURE 8 is a cross-sectional view VIII- VIII of FIGURE 7.

FIGURE 1 shows a dial plate 1 perced by openings 2 and 3 through which pass the feet 4 and 5 of a sign in relief 6. The length of the feet exceeds slightly the thickness of the dial plate 1.

After having placed all the signs on the dial plate, there taken along is laid on the ends of feet 4 and 5 a piece 8 heated to a temperature sufiicient to bring the feet to a plastic or flowing state on at least a part of their length. There is simultaneously exerted an axial pressure on the extremity of the feet by means of piece 8 in order to make the liquified material occupy completely openings 2 and 3 as shown on FIGURE 2. The attachment of the sign is obtained after cooling owing to the adherence of the solidified plastic material against the walls of openings 2 and 3. In efect these walls present minuscule roughened areas resulting from piercing thereof to which the liquified material becomes rigidly attached through the influence of the pressure exerted by tool 8.

It is evident that sign 6 can be secured by means of a single foot shown on FIGURE 3. In this modification of the invention the foot can fbe advantageously given a cross-sectional shape other than circular, for example, square as shown on FIGURE 4. The shape of the crosssection will permit to exactly position the time sign, the

foot being introduced in an opening 10 having a corresponding shape, and provided in the dial plate. The attachment will take place in the same manner as in the first embodiment.

The foot can also be given a crcular cross-section as shown in FIGURE 5 by positioning the sign in an imprint presenting the negative of the back of the dial or by any other means.

Another modification resides in the flaring of the openings 2 and 3 so as to for-m a housing or lodging 7 in which the plastified materials spread under the pressure of member 8.

FIGURES 8 and 9 show by way of example a device for carrying out this process wherein members 8 are integral with a common support 11 containing electrical resistance 12.

The source of heat naturally can be of another nature, ultra-sonic or chemical for example.

The process according to the invention is not limited to the securing of time signs on finished or unfinished dials, but can also be used for attaching any other elements on the dials, such as a ring, segment, circle, Symbol, trademark or other decorative element.

Naturally many types of plastic materials can be used in the practice of the claimed invention and the temperatures at which the process will be carried out will depend on the softening point of these plastic materials, all of which are well known to those skilled in the art. As examples of suitable plastic materials, there may be used polystyrene, polyethylene, epoxy resins, and in general any hard plastic resinous materials having an appreciable resistance to wear and which can be softened at a reasonably low temperature. Naturally the plastic material constituting the time indicia can be metallized or can have incorporated therein various colouring agents so as to give them the desired colour.

What is claimed is:

1. A timepiece dial comprising a dial plate of a given thickness and having a plurality of openings therein, said openings having rugosities in the walls thereof, said openings being postioned in areas where time signs are desired, a plastic time sign sitting over each of said openings, said time sign having at least one projection sitting in said opening and fused to `said rugosities in said opening.

2. A timepiece dial according to claim 1, wherein said projection, before being fused to said dial, has a length greater than said thickness of said dial.

3. Dial according to claim 1, wherein said openings are flared outwardly toward the back of said plate.

4. Dial according to claim 1, wherein said time signs are made of a plastic material selected from the group polystyrene, polyethylene and epoxy resins,

3 5. Dial according to claim 4, wherein said time signs 1,436,058 are metallized. 74,040 6. Dial according to claim 4, wheren said time signs 320,002. contain coloring agents. 340,448 References Cited 5 353'682 UNITED STATES PATENTS 3,277,562 10/ 1966 Huguenin 29-177 FOREIGN PATENTS RICHARD B. WILKINSON, Pr'ma'y Exan''ner,

S. R. WAL, Assistant Exam'ner.

U.S. CI. X.R. 

